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2985967 | Homologous recombination catalyzed by human cell extracts. | Two plasmids containing noncomplementing and nonreverting deletions in a bacterial phosphotransferase gene conferring resistance to neomycin (Neor) were incubated with human cell extracts, and the mixtures were used to transform recombination-deficient (recA-) Escherichia coli cells. We were able to obtain Neor colonie... |
3921405 | Studies of extracellular fibronectin matrix formation with fluoresceinated fibronectin and fibronectin fragments. | Fluorescein isothiocyanate conjugated human plasma fibronectin, 70-kDa collagen-binding, 60-kDa central, 60-kDa heparin-binding, 180-kDa heparin, collagen-binding fibronectin fragments and gelatin were used to study extracellular fibronectin matrix formation. Exogenous fibronectin, gelatin, 70-kDa collagen-binding and ... |
3985626 | Effects of pH and exocyclic substitution on flavosemiquinone reactivity with redox proteins and inorganic oxidants. | The effect of pH on the reaction of free flavosemiquinone analogs generated by laser-flash photolysis with oxidized Chromatium vinosum high-potential iron-sulfur protein, other iron-containing redox proteins, and nonbiological one-electron oxidants has been investigated. The results demonstrate that the second-order ra... |
3856865 | The molecular electronic device and the biochip computer: present status. | The idea that a single molecule might function as a self-contained electronic device has been of interest for some time. However, a fully integrated version--the biochip or the biocomputer, in which both production and assembly of molecular electronic components is achieved through biotechnology-is a relatively new con... |
4039039 | Diacylglycerol in large alpha-actinin/actin complexes and in the cytoskeleton of activated platelets. | The interaction of the cytoskeleton with plasma membranes may be mediated by vinculin, alpha-actinin and other proteins; alpha-actinin can interact specifically with model membranes only if they contain diacylglycerol and palmitic acid. On stimulation of platelets by thrombin, which leads to a reorganization of the cyt... |
3920226 | Acrosomal reaction of the Thyone sperm. III. The relationship between actin assembly and water influx during the extension of the acrosomal process. | In an attempt to investigate the role of water influx in the extension of the acrosomal process of Thyone sperm, we induced the acrosomal reaction in sea water whose osmolarity varied from 50 to 150% of that of sea water. (a) Video sequences of the elongation of the acrosomal processes were made; plots of the length of... |
3156849 | Copy mutant of mini-Rts1: lowered binding affinity of mutated RepA protein to direct repeats. | Nucleotide sequence analysis of mini-Rts1 and its copy mutant disclosed the presence of two clusters of direct-repeat sequences flanking the coding region for the 33,000-dalton RepA protein and two base substitutions on the mini-Rts1cop1 genome (Kamio et al., J. Bacteriol. 158:307-312, 1984). On subcloning of the left ... |
2984182 | Manipulation of intracellular magnesium content in polymyxin B nonapeptide-sensitized Escherichia coli by ionophore A23187. | Escherichia coli B cells were sensitized to ionophore A23187 by polymyxin B nonapeptide, and the induced magnesium and potassium ion fluxes were studied. Combined ionophore treatment permeabilized the cytoplasmic membrane of E. coli in an ion-specific manner and allowed the manipulation of intracellular Mg2+ content fr... |
3884587 | Locations of hook-associated proteins in flagellar structures of Salmonella typhimurium. | Hooks of the flagella of Salmonella typhimurium were purified from an flaL mutant. Hook-associated proteins, namely HAP1, HAP2, and HAP3, were separated from them, and the antibody against each HAP was prepared. By immunoelectron microscopic observation, these three kinds of antiHAP antibodies were found to bind on the... |
3980095 | Purification and characterization of an extracellular cytolysin produced by Vibrio vulnificus. | An extracellular cytolytic toxin produced by the halophilic bacterium Vibrio vulnificus was isolated free of detectable contamination with medium constituents and other bacterial products by sequential ammonium sulfate precipitation, gel filtration with Sephadex G-75, hydrophobic interaction chromatography with phenyl-... |
3883922 | Immunodiagnosis of human malignancy. | Definition of normal cell membrane antigens using immunologic techniques has permitted investigators to distinguish normal cells from malignant cells. Malignant cells express fetal antigens in concentrations different from normal mature cells. Mutant cells express differentiation as well as those antigens reflecting th... |
3973985 | Virus-receptor interaction in the adenovirus system: characterization of the positive cooperative binding of virions on HeLa cells. | The established positive cooperativity of adenovirus 2 binding to HeLa cells revealed a strong temperature dependence. The degree of cooperativity, quantified by means of Hill coefficients, progressively increased from 10 degrees C to reach a maximum level, which was maintained between 20 and 37 degrees C. On the other... |
19431591 | Resonance Raman spectra of photodissociated hemoglobins: implications on cooperative mechanisms. | Resonance Raman spectra at cryogenic temperatures of photodissociated hemoglobins and the corresponding deoxygenated preparations are compared and significant differences are found in modes with contributions from peripheral substituents of the heme as well as in the iron-histidine stretching mode. These differences in... |
3002015 | Modification of simian virus 40 large tumor antigen by glycosylation. | The SV40-encoded transforming protein, large tumor antigen (T-ag), is multifunctional. Chemical modifications of the T-ag polypeptide may be important for its multifunctional capacity. T-ag is additionally modified by glycosylation. T-ag was metabolically labeled in SV40-infected cells with tritiated galactose or gluco... |
2414973 | The effect of crown ethers on ionic currents in myelinated nerve fibres from Xenopus laevis. | The effect of several crown ethers on the currents at the node of Ranvier was studied. At differing potencies they caused a time- and potential-dependent inactivation of potassium permeability and a time- and potential-independent decrease in sodium permeability. The relative effect on potassium and sodium systems vari... |
3894569 | Extracellular polymer of Candida albicans: isolation, analysis and role in adhesion. | Extracellular polymeric material (EP) was isolated from culture supernatants of Candida albicans grown on carbon sources (50 mM-glucose, 500 mM-sucrose or 500 mM-galactose) known to promote yeast adhesion to different extents. Galactose-grown yeasts, which are the most adherent, produced more EP than sucrose-grown orga... |
4015790 | Wound healing. | The majority of wounds encountered in the accident and emergency department are superficial in nature and a consequence of accidental trauma or the elective surgical incision of infected foci. The techniques of management of such cases have undergone few changes in recent years, and any advances of a practical or thera... |
3924794 | [Effects of 2-benzyloxycarbonylphenyl trans-4-guanidinomethylcyclohexanecarboxylate hydrochloride monohydrate (TKG01) and its clathrate compound with beta-cyclodextrin (TA903) on experimental gastric ulcers and gastric secretion in rats]. | Effects of TKG01 on gastric ulcers and gastric secretion in rats were investigated in comparison with those of TA903, which is the equimolar clathrate compound of TKG01 anhydride with beta-cyclodextrin. The doses were adjusted on a molecular weight basis to include the same amount of TKG01 anhydride. Water-immersion st... |
2987840 | The TGGCA protein binds to the MMTV-LTR, the adenovirus origin of replication, and the BK virus enhancer. | TGGCA-binding proteins are nuclear proteins with high affinity for double-stranded DNA homologous to the prototype recognition sequence 5'YTGGCANNNTGCCAR 3'. Their ubiquitous tissue distribution in higher vertebrates characterizes them as a class of highly conserved proteins which may exert a basic function. To obtain ... |
4000941 | Biotin-labeled synthetic oligodeoxyribonucleotides: chemical synthesis and uses as hybridization probes. | Oligodeoxynucleotides have been selectively labeled with biotin at their 5'-termini through an aminoalkylphosphoramide linker arm by an efficient chemical method. The reactions were performed in aqueous solution on unprotected oligonucleotides and were insensitive of the sequence and length of the oligonucleotide. 5'-b... |
3873543 | MgATP specifically controls in vitro self-assembly of vertebrate skeletal myosin in the physiological pH range. | The appearances in the electron microscope of rat and rabbit skeletal muscle myosin filaments and rod aggregates, formed in the presence of variable amounts of MgATP, were compared at different pH values. It is shown that small amounts of MgATP, similar to those sufficient to trigger the dissociation of the actomyosin ... |
2581783 | Homologies between paraflagellar rod proteins from trypanosomes and euglenoids revealed by a monoclonal antibody. | A Nonidet P 40 insoluble fraction was isolated from Trypanosoma brucei and was used to raise a monoclonal antibody (5E9). The antigen was localized by indirect immunofluorescence in the flagellum of T. brucei and of two species of euglenoids, Euglena gracilis and Distigma proteus. In immunoblot analysis, 5E9 appeared t... |
3995100 | [Interaction between cytochrome P-448 and NADP-cytochrome P-450 reductase in reconstituted microsomal membranes]. | The regularities of changes in the functional activity of the microsomal monooxygenase system reconstituted by self-assembly from intact rat liver microsomes solubilized with 4% sodium cholate were studied at variable levels of NADPH-cytochrome P-450 reductase and the 3-methylcholanthrene-induced form of cytochrome P-4... |
3838893 | Studies on the inhibition of ferrochelatase by N-alkylated dicarboxylic porphyrins. Steric factors involved and evidence that the inhibition is reversible. | The structural requirements for the inhibition of ferrochelatase by N-alkylated porphyrins were investigated and experiments carried out to explore the mechanism of enzyme inhibition. Three dicarboxylic porphyrins, all substrates of the enzyme, are strongly inhibitory when N-alkylated; in contrast, uroporphyrin and cop... |
3993977 | Assemblies of linear arrays of particles in the apical plasma membrane of mitochondria-rich cells in the gill epithelium of the Atlantic hagfish (Myxine glutinosa). | In the gill epithelium of the Atlantic hagfish Myxine glutinosa a mitochondria-rich cell type is described which ultrastructurally resembles the chloride cells in other fish species. Freeze-fracture replicas reveal different supramolecular structures in the luminal plasma membrane and in the intracellular amplification... |
2985952 | Generation of helper-free amphotropic retroviruses that transduce a dominant-acting, methotrexate-resistant dihydrofolate reductase gene. | We constructed several retroviruses which transduced a mutant dihydrofolate reductase gene that was resistant to methotrexate inhibition and functioned as a dominant selectable marker. The titer of dihydrofolate reductase-transducing virus produced by virus-producing cells could be increased to very high levels by sele... |
3986526 | Tropic factors in reactive mammalian central nervous system tissue. | Previous studies suggest that distal stumps of transected peripheral nerves contain diffusible factors which can attract/support axonal regeneration over distances of several mm in vivo. The present experiments were undertaken to determine if this is so for distal regions of traumatized central (i.e., optic) nerves. Pr... |
2985061 | Solubilisation of ferricytochrome c in methanol using a crown ether: absorption, circular dichroism and EPR spectral properties. | Ferricytochrome c is normally insoluble in methanol, but its solution is facilitated by complexation with 18-crown-6. Absorption, circular dichroism and EPR spectroscopy indicate that the solubilised protein in MeOH exists in at least three conformational states, all different from the native state in neutral aqueous s... |
3856850 | Channels formed by botulinum, tetanus, and diphtheria toxins in planar lipid bilayers: relevance to translocation of proteins across membranes. | The heavy chains of both botulinum neurotoxin type B and tetanus toxin form channels in planar bilayer membranes. These channels have pH-dependent and voltage-dependent properties that are remarkably similar to those previously described for diphtheria toxin. Selectivity experiments with anions and cations show that th... |
3982379 | [Mitral valve replacement with preservation of the posterior leaflet, chordae tendineae and papillary muscles (modified MVP)]. | The modified MVR leaving the posterior leaflet and its subvalvular tissues intact was performed in 40 patients including 17 of MR, 17 of MSR and 6 of MS from 1981 to 1984 in this institution. Mitral valves were replaced mostly with mechanical valves and using interrupted everting mattess sutures. Moreover, the aortic v... |
3156879 | Cigarette smoke can activate the alternative pathway of complement in vitro by modifying the third component of complement. | Cigarette smoking is associated with significant increases in the number of pulmonary mononuclear phagocytes and neutrophils. A potent chemoattractant for these cells is C5a, a peptide generated during complement (C) activation. We, therefore, investigated the possibility that cigarette smoke could activate the complem... |
2983088 | Inhibition of cellular DNA polymerase alpha and human cytomegalovirus-induced DNA polymerase by the triphosphates of 9-(2-hydroxyethoxymethyl)guanine and 9-(1,3-dihydroxy-2-propoxymethyl)guanine. | The triphosphates of 9-(2-hydroxyethoxymethyl)guanine and 9-(1,3-dihydroxy-2-propoxymethyl)guanine were examined for their inhibitory effect on highly purified cellular DNA polymerase alpha and human cytomegalovirus (Towne strain)-induced DNA polymerase. These two nucleoside triphosphates competitively inhibited the in... |
3972901 | Myosin and paramyosin are organized about a newly identified core structure. | Myosin isoforms A and B are differentially localized to the central and polar regions, respectively, of thick filaments in body wall muscle cells of Caenorhabditis elegans (Miller, D. M. III, I. Ortiz, G. C. Berliner, and H. F. Epstein, 1983, Cell, 34:477-490). Biochemical and electron microscope studies of KCl-dissoci... |
3972839 | Chloroplast biogenesis. Molecular structure of chlorophyll b (E489 F666). | Nuclear magnetic resonance analysis established the presence of two vinyl groups/macrocycle of chlorophyll b (E489 F666). The latter is the only chlorophyll b that accumulates in a corn mutant (ON 8147). On the other hand the presence of only one vinyl group/macrocycle of authentic monovinyl chlorophyll b (E475 F660) w... |
2982854 | Ferritin and superoxide-dependent lipid peroxidation. | Ferritin was found to promote the peroxidation of phospholipid liposomes, as evidenced by malondialdehyde formation, when incubated with xanthine oxidase, xanthine, and ADP. Activity was inhibited by superoxide dismutase but markedly stimulated by the addition of catalase. Xanthine oxidase-dependent iron release from f... |
3918984 | Differential expression of protein S genes during Myxococcus xanthus development. | Protein S, the most abundant protein synthesized during development of the fruiting bacterium Myxococcus xanthus, is coded by two highly homologous genes called protein S gene 1 (ops) and protein S gene 2 (tps). The expression of these genes was studied with fusions of the protein S genes to the lacZ gene of Escherichi... |
19431588 | Geometry for the Primary Electron Donor and the Bacteriopheophytin Acceptor in Rhodopseudomonas viridis Photosynthetic Reaction Centers. | The tetrapyrrole electron donors and acceptors (bacteriochlorophyll, BCh; bacteriopheophytin, BPh) within the bacterial photosynthetic reaction center (RC) are arranged with a specific geometry that permits rapid (picosecond time scale) electron tunneling to occur between them. Here we have measured the angle between t... |
16346749 | Differential Adhesion and Infection of Nematodes by the Endoparasitic Fungus Meria coniospora (Deuteromycetes). | The conidia of the endoparasitic fungus Meria coniospora (Deuteromycetes) had different patterns of adhesion to the cuticles of the several nematode species tested; adhesion in some species was only to the head and tail regions, on others over the entire cuticle, whereas on others there was a complete lack of adhesion.... |
2861191 | Topography in relation to activity of the F1-ATPase of Micrococcus lysodeikticus (M. luteus): a study using trypsin digestion and hydrophobic interaction chromatography. | Micrococcus lysodeikticus (M. luteus) ATPase digested in a controlled manner with trypsin behaves like the native protein when chromatographed on alkyl agarose supports. The enzyme immobilized on the supports through noncovalent interaction is able to hydrolyze ATP with a specific activity similar to that of native mem... |
3989695 | Quantitative structure-stability relationships among inclusion complexes of cyclodextrins. I: Barbituric acid derivatives. | Quantitative structure-stability relationships (QSSRs) are formulated for the inclusion complexation of 17 barbituric acid derivatives with alpha- and beta-cyclodextrin. The variation in the complex stability constants K alpha and K beta is found to be partly accounted for by the molar refractivity or the hydrophobicit... |
3986613 | Growth and restriction of the ipsilateral retinocollicular projection in the opossum. | The distribution of optic nerve fibers and terminals in the superior colliculus (SC) was followed throughout its development in pouch young opossums in order to establish the normal sequence of events leading to the formation of mature patterns. Up to 7 days of life in the pouch, labeled fibers can be followed only as ... |
2983329 | Determination of the stereostructure of the product of Tn3 resolvase by a general method. | A method has been developed for determination of the absolute structure of DNA catenanes. The catenated DNA is partially denatured before being thickened with a coating of RecA protein and spread for electron microscopy. This treatment allows visualization of the orientation of each ring as well as identification of th... |
2857557 | 13C nuclear magnetic resonance studies on bacteriochlorophyll a biosynthesis in Rhodopseudomonas spheroides S. | The 13C NMR spectra were analyzed in bacteriochlorophyll a and magnesium protoporphyrin methyl ester formed in Rhodopseudomonas spheroides S. in the presence of L-[1-13C]glutamate and [2-13C]glycine. After reassignment of three alpha-pyrrolic carbons (C-9, -14 and -16) of bacteriochlorophyll a, the spectra showed that ... |
2982314 | A comparative study of the resonance Raman spectra of bacterial cytochromes. | Resonance Raman spectra were obtained for two newly isolated bacterial cytochromes, Alcaligenes faecalis (ATCC 8750) c554 and Alcaligenes faecalis c556. Their spectra were compared with those of mammalian cytochrome c and two other bacterial cytochromes, Paracoccus denitrificans c550 and Pseudomonas aeruginosa c551. Th... |
2578575 | HBc and HBe antigenicity and DNA-binding activity of major core protein P22 in hepatitis B virus core particles isolated from the cytoplasm of human liver cells. | Highly purified hepatitis B virus core particles were obtained in large amounts from the cytoplasm of infected human liver cells. This DNA polymerase-negative core preparation had only hepatitis B core antigen-specific antigenicity and showed a surprising stability. Two forms of a single protein of 22,000 molecular wei... |
2982023 | A physical domain of herpes simplex virus ICP8 is expressed and active in Escherichia coli. | In this report, we describe a series of procedures to assay the function of fusion genes in Escherichia coli and the specific application to the carboxy-terminal third of the herpes simplex virus type 1 (HSV-1) DNA-binding protein ICP8. E. coli cells containing the cloned HSV-1 BamHI G fragment with the HSV-1 BamHI-G-V... |
17821215 | Supramolecular chemistry: receptors, catalysts, and carriers. | Supramolecular chemistry is the study of the structures and functions of the supermolecules that result from binding substrates to molecular receptors. Macropolycyclic receptors and coreceptors have been designed that form cryptate inclusion complexes and display molecular recognition towards spherical, tetrahedral, an... |
2428369 | Membrane damage by channel-forming proteins: staphylococcal alpha-toxin, streptolysin-O and the C5b-9 complement complex. | One mechanism through which cells can be damaged involves insertion of alien proteins into the membrane bilayer and the formation of hydrophilic transmembrane pores. Three examples for this process are discussed, namely membrane damage by staphylococcal alpha-toxin, streptolysin-O, and by the terminal C5b-9 complement ... |
2872134 | Effect of heptakis (2,6-0-dimethyl)beta-cyclodextrin on cell growth and the production of pertussis toxin and filamentous hemagglutinin in Bordetella pertussis. | Heptakis (2,6-0 dimethyl)beta-cyclodextrin (MeCD) which permits the growth of single colonies of Bordetella pertussis Tohama phase I on Stainer-Scholte medium solidified with agar also enhanced the production of pertussis toxin (PT). More than one hundred times the amount of PT was produced in Stainer-Scholte medium wi... |
3913907 | Presence of neuromedin B-like immunoreactivity in the brain and gut of rat and guinea-pig. | A recently developed specific radioimmunoassay for neuromedin B, originally isolated from porcine spinal cord, was used to investigate its distribution in rat and guinea-pig brain and gut. In both species, neuromedin B-like immunoreactivity was present in several regions of brain, and high concentrations occurred in th... |
3867675 | Characterization of Chlamydomonas sexual agglutinins. | Molecules (agglutinins) mediating mating-type-specific adhesion of Chlamydomonas reinhardtii plus and minus gametes have been purified and shown to be homologous by several criteria. Both are large, extrinsic glycoproteins, rich in hydroxyproline and serine, which to a variety of inactivating agents. Direct visualizati... |
3910300 | Progress in enzyme immunoassays: production of reagents, experimental design, and interpretation. | Enzyme immunoassays represent in many cases the preferred procedure for the detection of antigens or corresponding antibodies. However, many of the current procedures are performed suboptimally. This article reviews the available designs, auxiliary recognition systems, production and purification of antibodies, conjuga... |
4079975 | Cyclodextrins: a new group of industrial basic materials. | Adequate toxicological studies, discovery of numerous potential fields of utilization and last but not least, the production of cyclodextrins on industrial scale with high homogeneity and low price led to their recognition as a new group of industrial basic materials. Until now cyclodextrins were considered merely as a... |
4077919 | The inhibitory effect of 4-chloro-2-(2,6-dichloro-4-hydroxyphenyl)-1-ethyl-6-hydroxyindole (D 15413) on estrogen-dependent mammary tumors. | The antineoplastic activity of 4-chloro-2-(2,6-dichloro-4-hydroxyphenyl)-1-ethyl-6-hydroxyindole (D 15413) was determined in several estrogen-dependent mammary tumor models. The growth of DMBA-induced rat mammary carcinomas was inhibited by doses ranging from 2 to 18 mg/kg. A dose of 6 X 12 mg/kg per week p.o. reduced ... |
4072085 | [Damage to the supramolecular DNA complex in the mechanism of action of antitumor drugs]. | The report deals with damaging effects on the structure of a supramolecular DNA complex of leukemic cells in P388 mice, susceptible to most antitumor preparations, following treatment with therapeutic doses of sarcolysin, methylnitrosourea, actinomycin D and adriamycin. Capillary elastoviscosimetry and nucleoid sedimen... |
2933104 | Twisted architectures in cell-free assembled collagen gels: study of collagen substrates used for cultures. | Reprecipitated fibrils from collagen solutions assemble into aggregates often showing a remarkable twisted structure. We first observed these aggregates in collagen gels prepared to facilitate culture of epithelial cells. We verified that these structures form in the absence of cells and correspond to a process of self... |
4052138 | Absorption, distribution, excretion and metabolism of orally administered 14C-beta-cyclodextrin in rat. | The absorption, distribution, excretion and metabolism of orally administered universally labelled 14C-beta-cyclodextrin and 14C-glucose were compared in rat. The maximum radioactivity of the blood derived from 14C-beta-cyclodextrin was observed between 4th and 11th h and the value of the maximum in different experimen... |
4048020 | [Changes in the supramolecular organization of polyurethaneurea-acylsemicarbasides in the process of their biodestruction]. | Using the scanning electron microscope changes in supramolecular organization of polyurethane, (polyurethanecarbamideacylsemicarbasides), having in the main polymer chain foci of tripeptide were studied. They were subjected to proteolytic enzyme action and implanted into animal organisms. It was found that erosive proc... |
3930009 | [Inactivation of soman by beta-cyclodextrin]. | Soman (pinacolyl methylphosphonofluoridate), a mixture of four stereoisomers, is inactivated appreciably in Tris buffer, pH 7.40, mu = 0.155 at 25 degrees C by beta-cyclodextrin (cycloheptaamylose, beta-CD). Under these conditions, the dissociation constant Kd of the 1:1 complex formed by beta-CD and soman and the rate... |
3161697 | Interferometric evaluation of collagen concentration in tendon fibers. | The dry mass concentration of collagen in native rat tail tendon fibers was studied by interferometric techniques. It could be shown that the collagen concentration of rat tail tendon fibers is not constant nor does it vary uniformly with the fiber diameter. Evidence is presented that the collagen concentration shows s... |
4026780 | Internalization of cycloheptaamylose-dansyl chloride complex during labelling of surface membrane in living Paramecium aurelia cells. | Internalization of cycloheptaamylose-dansyl chloride complex during surface labelling of living long-term starved Paramecium aurelia cells has been observed. This process may be inhibited by pretreatment of the ciliates with dichloroisoproterenol. Uptake of cycloheptaamylose-dansyl chloride may be visualized only after... |
4017552 | Comparative analyses of aortic type IV collagen in various species. | Aortic type IV collagen from several species contained identical patterns of high-molecular-weight aggregates as determined by HPLC. Slab gel electrophoresis in one and two dimensions revealed a similar chain composition in these collagen samples. The basic structural components were similar in size to the long form of... |
4001851 | An ultrastructural analysis of the physical organization of collagenous (type I) matrices: one determinant of urothelium maintenance in vitro. | Collagenous matrices, used as cell culture substrata, can be prepared from different collagen types in a variety of forms using a range of polymerization procedures. Type I collagen has been most frequently used either as dried collagen films or hydrated collagen gels. Sheets of isolated bladder urothelium, when plated... |
3158340 | Transient-state kinetics of the ADP-insensitive phosphoenzyme in sarcoplasmic reticulum: implications for transient-state calcium translocation. | The kinetics of formation of the ADP-sensitive (EP) and ADP-insensitive (E*P) phosphoenzyme intermediates of the CaATPase in sarcoplasmic reticulum (SR) were investigated by means of the quenched-flow technique. At 21 degrees C, addition of saturating ADP to SR vesicles phosphorylated for 116 ms with 10 microM ATP gave... |
3157455 | Studies of the inhibition by malto-oligosaccharides of the cyclisation reaction catalysed by the cyclodextrin glycosyltransferase from Klebsiella pneumoniae M 5 al with glycogen. | The substrate qualities of malto-oligosaccharides for the disproportionation reaction catalysed by the cyclodextrin glycosyltransferase [(1----4)-alpha-D-glucan:[(1----4)-alpha-D-glucopyranosyl]transferase (cyclising) EC 2.4.1.19] from Klebsiella pneumoniae M 5 al have been re-investigated. Maltose failed to be homolog... |
3980561 | Survival of human bone marrow cells after in vitro treatment with 12 anticancer drugs and implications for tumor drug sensitivity assays. | We investigated the responsiveness of human normal granulocyte-macrophage colony-forming units in culture (GM-CFUC) continuously exposed in vitro to 1 of 12 anticancer drugs. All drugs except bleomycin showed a simple negative exponential dose-survival curve. The in vitro toxicity of drugs in GM-CFUC did not always cor... |
2984019 | Are the toxicities of pentobarbital and ethanol mediated by the GABA-benzodiazepine receptor-chloride ionophore complex? | Both barbiturates and ethanol have been reported to interact with the GABA-benzodiazepine receptor-chloride ionophore 'supramolecular complex'. These observations raise the possibility that some of the pharmacologic actions of barbiturates and ethanol may be mediated through this complex. In this study we have administ... |
2857160 | Disulfide-mediated interactions of the chlamydial major outer membrane protein: role in the differentiation of chlamydiae? | The effects of exogenous reducing agents on a number of biological properties of purified Chlamydia trachomatis LGV-434 and Chlamydia psittaci meningopneumonitis elementary bodies (EBs) have been examined in an attempt to identify in vitro correlates of early events in the differentiation of the infectious EB to the re... |
2981625 | Recombination site selection by Tn3 resolvase: topological tests of a tracking mechanism. | In vitro recombination by Tn3 resolvase of plasmids containing two directly repeated recombination (res) sites generates two singly interlinked catenated rings. This simple product catenane structure was maintained over a wide range of substrate supercoil densities and in a reaction mixture in which phage lambda Int-me... |
2578272 | Lignoceroyl-CoA ligase activity in rat brain microsomal fraction: topographical localization and effect of detergents and alpha-cyclodextrin. | Lignoceroyl-CoA ligase activity has been detected in microsomal fractions prepared from rat brain. The synthesis of lignoceroyl-CoA from [1-14C]lignoceric acid and CoASH by this enzyme had an absolute dependence on ATP and Mg2+; ATP could not be replaced by GTP [I. Singh, M. S. Kang, and L. Phillips (1982) Fed. Proc. 4... |
2578122 | Factors affecting binding of galacto ligands to Actinomyces viscosus lectin. | The specificity requirements for the binding of Actinomyces viscosus T14V were examined by testing simple sugars, oligopeptides, and glycoproteins as inhibitors of the aggregation of glycoprotein-coated latex beads and washed A. viscosus cells. Lactose was the most inhibitory simple sugar; D-fucose and D-galactose were... |
3880730 | Mechanism of membrane damage by streptolysin-O. | Streptolysin-O (SLO) is a thiol-activated, membrane-damaging protein toxin of Mr 69,000 that is produced by most strains of beta-hemolytic group A streptococci. Native, primarily water-soluble toxin molecules bind to cholesterol-containing target membranes to assemble into supramolecular curved rod structures (25 to 10... |
3880722 | Role of the carbohydrate domains of glycophorins as erythrocyte receptors for invasion by Plasmodium falciparum merozoites. | Solubilized preparations of purified glycophorins and specific domains of these molecules were assessed for their effects as inhibitors of Plasmodium falciparum invasion of human erythrocytes in vitro. The ability of newly invaded merozoites to continue developing and incorporating [3H]hypoxanthine during a 24-h period... |
11539651 | A model for the origin of photosynthesis--III. The ultraviolet photochemistry of uroporphyrinogen. | The photochemical ramifications of the high ultraviolet flux on the primordial earth prior to the formation of the ozone layer have been considered in a study of the ultraviolet photochemistry of uroporphyrinogen (urohexahydroporphyrin), a colorless compound which absorbs strongly at wavelengths less than 220 nanometer... |
22055634 | Electron microscopic studies of artificial supramolecular structures from collagen solutions. | Changes in the molecular structure of collagen fibrils isolated from solutions of native tropocollagen (TC) and of soluble collagen, obtained by enzymic (ESC) and alkaline-salt (ASC) methods, were studied by electron microscopy. It was found that, under certain conditions, it is possible to derive native-like fibrils (... |
3558548 | Mobile phase effects on the separations of substituted anilines with a beta-cyclodextrin-bonded column. | The capacity factors of several substituted anilines were measured on a beta-cyclodextrin (beta-CD)-bonded column with mobile phases varying from the classical, normal-phase condition, e.g. n-heptane-2-propanol, to the classical, reversed-phase condition, e.g. water-2-propanol. Different modifiers, such as acetonitrile... |
3104022 | Species differences in pharmacokinetics and drug teratogenesis. | Interspecies differences in regard to the teratogenicity of drugs can be the result of differing pharmacokinetic processes that determine the crucial concentration-time relationships in the embryo. Maternal absorption, as well as distribution, of the drugs does not usually show great species differences. The first-pass... |
3817027 | Patterns of crystallin expression during differentiation in vitro of several chick genotypes with different effects on lens cell growth rate. | We have recently reported that chick lens cells during differentiation in long-term culture show a programme of change in crystallin expression which mimics events during lens development in vivo. The aim of the present work was to examine the stability of the programme by testing the response to genetic influences and... |
3028782 | DNA sequences required for expression of a Dictyostelium actin gene. | A 2.8-kb fragment of 5' non-coding DNA from the Dictyostelium actin 15 gene has previously been shown to contain all of the cis-acting DNA sequence elements required for normal developmentally-regulated transcription of actin gene fusion RNAs when reintroduced into the genome by DNA-mediated transformation. Deletion an... |
3545816 | Purification and characterization of a T cell specific serine proteinase (TSP-1) from cloned cytolytic T lymphocytes. | We describe the purification of a T cell specific serine proteinase derived from a cloned murine cytolytic T lymphocyte line. Analysis of the enzyme by sodium dodecyl sulfate polyacrylamide gel electrophoresis revealed a mol. wt of approximately 60 kd under non-reducing conditions and of approximately 30 kd under reduc... |
3816757 | Purification and properties of a new clathrin assembly protein. | A clathrin assembly protein (AP180) has been purified and characterized from coated vesicles of bovine brain. This protein has hitherto escaped detection because in SDS-gel electrophoresis it is obscured by the 180 kd heavy chain of clathrin. Despite the similarity in electrophoretic mobility, AP180 differs from clathr... |
3813518 | Comparative efficacy of ketoconazole and mebendazole in experimental trichinosis. | The therapeutic efficacy of ketoconazole and mebendazole was studied in ICR/CD-1 mice infected with Trichinella spiralis for 17 to 20 weeks. Efficacy of both drugs was over 70% when compared with results in control mice. This study indicates that both ketoconazole and mebendazole should be considered in the treatment o... |
3808954 | Three-arm nucleic acid junctions are flexible. | Nucleic acid junctions are stable analogs of branched DNA structures which occur transiently in living systems. We show here that junctions which contain three double helical arms can be enzymatically oligomerized, using conventional sticky-ended ligation procedures, to create larger complexes. The products consist of ... |
3808946 | Circular dichroism of two conformations of poly[d(G-C)] induced by low pH. | Circular dichroism (CD) and UV absorption data showed that poly[d(G-C)] (at 0.09M NaCl, 0.01M Na+ (phosphate), 20 degrees C) underwent two conformational transitions upon lowering of the pH by the addition of HCl. The first transition was complete at about pH 3.0. The second transition was complete upon lowering the pH... |
3801570 | Fibrin assembly. Lateral aggregation and the role of the two pairs of fibrinopeptides. | The structural basis of the wide variability of the physical properties of fibrin clots and the process of assembly of the clot were investigated by electron microscopy of fibers formed under various ionic conditions. In addition, highly specific proteolytic enzymes from different snake venoms were used to remove selec... |
2948567 | Transmembrane gradient and ligand-induced mechanisms of adenosine 5'-triphosphate synthesis by sarcoplasmic reticulum adenosinetriphosphatase. | A series of experiments was performed in order to characterize ATP formation by sarcoplasmic reticulum adenosinetriphosphatase (ATPase). Comparative measurements were obtained by using native and leaky vesicles, in the presence and in the absence of a transmembrane Ca2+ gradient. ATP formation was started by addition o... |
3541640 | Detection of urothelial Lewis antigens with monoclonal antibodies. | The detectability of Lewis a and b antigens (Lea, Leb) was examined in the normal urothelium of 28 human subjects whose red blood cells (RBCs) were also tested for Lea and Leb. Mouse monoclonal antibodies as well as goat and human antisera were used on paraffin-processed and fresh-frozen tissues. Multiple biopsy specim... |
2432600 | Antibodies to the binding site of the receptor for luteinizing hormone-releasing hormone (LHRH): generation with a synthetic decapeptide encoded by an RNA complementary to LHRH mRNA. | A molecular recognition code has been hypothesized to exist in which ligands and their binding sites are encoded on complementary segments of genomic DNA. We have tested this hypothesis by generating a rabbit antibody to a synthetic decapeptide (complementary peptide) encoded by an RNA complementary to the mRNA for lut... |
3099287 | Intracytoplasmic phosphorylation sites of Tac antigen (p55) are not essential for the conformation, function, and regulation of the human interleukin 2 receptor. | Tac antigen, the receptor for human interleukin 2 (IL-2), contains in its intracytoplasmic region a serine residue (Ser-247) that is seemingly the predominant site of protein kinase C-mediated phosphorylation. A number of studies on growth factor receptors have suggested the importance of phosphorylation in receptor st... |
3467329 | Systemic resistance to methotrexate in transgenic mice carrying a mutant dihydrofolate reductase gene. | A full-length cDNA coding for a mutant dihydrofolate reductase (DHFR; 5,6,7,8-tetrahydrofolate: NADP+ oxidoreductase, EC 1.5.1.3), cloned from a mouse fibroblast cell line grown in high concentrations of methotrexate (MTX), was microinjected into mouse embryos to produce transgenic mice. The DHFR cDNA product is 270-fo... |
2879282 | The homeo domain of a murine protein binds 5' to its own homeo box. | Nuclear protein extracts from day 12.5 mouse embryos were used to study protein binding to DNA sequences 5' of the Hox 1.5 homeo box. Embryos of this developmental stage are known to express this gene. DNA binding protein blotting and retardation gel techniques show that murine embryonic nuclear proteins specifically b... |
3467317 | Dynamic exchange of myosin molecules between thick filaments. | To examine thick filament assembly and myosin exchange, a fluorescence energy transfer assay has been established. Assembly-competent myosin molecules labeled with the sulfhydryl-specific fluorochromes 5-(2-[(iodoacetyl)-amino]ethyl)aminonaphthalene-1-sulfonic acids (IAEDANS) or 5-iodoacetamidofluorescein (IAF) were pr... |
3540940 | Synthesis, bacterial expression, and mutagenesis of the gene coding for mammalian cytochrome b5. | We have totally synthesized a gene that codes for rat hepatic cytochrome b5. The 5' flanking region was designed for efficient expression of this gene in Escherichia coli by incorporating an optimum ribosome binding site and spacer region. Both a soluble form, analogous to the protease-treated microsomal protein, as we... |
3467311 | Hemoglobin S Antilles: a variant with lower solubility than hemoglobin S and producing sickle cell disease in heterozygotes. | We have found a sickling variant, Hb S Antilles, alpha 2 beta 2(6 Glu----Val, 23 Val----Ile), that has the same electrophoretic mobility as Hb S but a distinct isoelectric focus and produces sickling in the carriers of the Hb A/S Antilles trait. The carriers' erythrocytes tend to sickle at O2 partial pressures similar ... |
3025651 | Multiple protein-binding sites in the 5'-flanking region regulate c-fos expression. | We tested sequences flanking the mouse c-fos gene for the ability to form specific DNA-protein complexes with factors present in crude nuclear extracts prepared from mammalian cells. Three such complexes were detected. One complex formed in a region necessary for the induction of c-fos expression by serum growth factor... |
2432071 | Acidic and basic hair/nail ("hard") keratins: their colocalization in upper cortical and cuticle cells of the human hair follicle and their relationship to "soft" keratins. | Although numerous hair proteins have been studied biochemically and many have been sequenced, relatively little is known about their in situ distribution and differential expression in the hair follicle. To study this problem, we have prepared several mouse monoclonal antibodies that recognize different classes of huma... |
2431413 | The permeability of gamma-aminobutyric acid-gated chloride channels is described by the binding of a "cage" convulsant, t-butylbicyclophosphoro[35S]thionate. | The "cage" convulsant t-butylbicyclophosphoro[35S]thionate ([35S]TBPS) binds with high affinity to sites at or near a gamma-aminobutyric acid (GABA)-gated chloride channel according to current hypothesis. We now report that the potencies of a series of anions in enhancing [35S]TBPS binding correlated highly with their ... |
3024169 | Sequence homology between acquired immunodeficiency syndrome virus envelope protein and interleukin 2. | A region of homology has been found between the envelope (env) protein of the acquired immunodeficiency syndrome (AIDS) virus and a portion of interleukin 2 (IL-2) that purportedly binds to the IL-2 receptor. This homology, between two proteins associated with opposing biological functions, suggests possible mechanisms... |
3782475 | Molecular defect in the membrane skeleton of blood bank-stored red cells. Abnormal spectrin-protein 4.1-actin complex formation. | During liquid preservation under blood bank conditions, red cell membranes inexorably undergo damage that decreases erythrocyte survival after transfusion. Accordingly, we have surveyed membrane skeletal protein interactions during storage. We uncovered a decrease in the in vitro formation of spectrin-actin complex in ... |
3782304 | The role of the main noncollagenous domain (NC1) in type IV collagen self-assembly. | Type IV collagen incubated at elevated temperatures in physiologic buffers self-associates (a) via its carboxy-terminal (NC1) domain, (b) via its amino-terminal (7S) domain, and (c) laterally; and it forms a network. When examined with the technique of rotary shadowing, isolated domain NC1 was found to bind along the l... |
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